Ground based flight simulating apparatus

ABSTRACT

In ground-based flight-simulating apparatus, a dummy flight deck is provided for the crew being trained and the dummy flight deck, with occupants, is moved to simulate at least pitch and roll movement of an aircraft in actual flight. The present invention comprises a dummy flight deck suspended from a supporting structure by three hydraulic jacks attached to the dummy flight deck. Differential action of the jacks provides pitch and bank motions and common action provides heave motion. A further pair of hydraulic jacks attached, on opposite sides of the flight deck centerline, provides yaw, surge and retardation motions. A further hydraulic jack, acting transversely of the flight deck centerline, provides sway motion.

United States Patent I l l lnvcntors Appl. No, Filed Patented Assignee Priority William Desmond Akister Aylesbury;

Meville Leslie Shelley, Haywards Heath, both ol, England Feb. 3, I969 Aug. I0, I97] Redilon Limited London, England Mar. 4, 1968 Great Britain US. Cl

Int. Cl 0090 9/08, 864g 7/00 Field 0| Search References Cited UNITED STATES PATENTS l/l 967 Cappel 3.304 628 2/1967 Kaplan 35/12 Primary Examiner- Robert W. Michell Assistant Examiner-L. R. Oremland Attorney-Larson, Taylor and Hinds ABSTRACT: in ground-based flight-simulating apparatus, a dummy flight deck is provided for the crew being trained and the dummy flight deck, with occupants, is moved to simulate at least pitch and roll movement of an aircraft in actual flight. The present invention comprises a dummy flight deck suspended from a supporting structure by three hydraulic jacks attached to the dummy flight deck. Differential action of the jacks provides pitch and bank motions and common action provides heave motion. A further pair of hydraulic jacks attached, on opposite sides of the flight deck centerline, provides yaw, surge and retardation motions. A further hydraulic jack, acting transversely of the flight deck centerline, provides sway motion.

V; P 118 g Q l re m9- '4 9 v 7 p 85 1 $9 6 V p4 Q A a 4&2

I m HA I 5 V18 4 P aiented Aug. 10, 1971 I 3,597,857

2 Sheets-Shed 1 Ema Aii 'ib. 197 1 2 Sheets-Shoat 2 LOAD HYDRAULIC PRESSURE H/PAS5 FILTER GROUND BASED FLIGHT SIMULATING-APPARATUS;

This invention relates to ground-based aircraft flight simulators in which movement of theflight deck of an aircraft is simulated in response to the operation of the-flyingcontrols.

Flight-training,apparatus is known in which a dummyfli'ght '1 deck is givenangularmovement around its pitchiandrollaxes,

in order to simulate the corresponding motion-of an:aircraft in actualflight. Such an apparatus is described in Briti'sh'Pat. No.

Unlikean aircraft in actual flight, however; a dummyflight" deck can be permitted onlylimited displacement or angular movement. Thus, means have beenproposed for restoring thcs dummy flight deck slowly to a reference positiom-after flightsimulated movement, so that such return is. imperceptible do" the occupants.

ln. modern aircraft, a considerable amount of physical disturbance is experienced by the crew when Irapid changes of 1' height or of direction are madeat highspeed. Such changes may result from maneuvers, efiected by the pilot orby the autopi lot, or may be caused. by. atmospheric turbulence; Consequently, a great deal of practice is required to operate successfullymany of the automatic and semiautomatic devices in-" stalled in such aircraft. It may be difficult or dangerous', unde'r platform 7 carriesa dummy flight'deck 8 having an entrance actual flying conditions, to determine whether the crew-are able to operate such devices satisfactorily. Training ofcrew -in' flight simulating apparatusthus provides aipreferably alt'rna tive'to training in actual flying operations.

It is anxobject of the present invention to provide grounds 0.

based apparatus in which a dummy flight deck of an aircraft s controlled to move. along and around severalaxes, so thatthe physical effects experienced by the crewof a high-speed air-' craft are, more realistically represented thanheretoforect.

Accordingly, the present invention-provides a ground-based 1 aircraft flightwsimulator including a dummy flightdeckof an" I aireraft mounted for simulated movement, including ;simtl'-'== lated movement about longitudinal. and- .transversewaxes thereof, having a pluralityof extensibleandretractabledrive members operablefor providingsaid simulated. movement;'4

first andsecond of said drivemembers beingattached to th'e dummy flightdeck atpoints spaced apart on opposite'sides-of the-longitudinal axis thereof andbeing operable fo'r up andw down movementof said attachmentpoints, a third one of'saiddrivemembers being attached to the dummy flight-ldeckata point on the opposite side of the transverseaxisfromsaid new and second'drive members arid being operable for upsand i downmovement of its said attachment point, afourthone ofsaid. drive members being attachedto'the' dummy flight d'cclt.

tachedto the dummy flight deck and.beingoperableforlateral'+5 movernentof its-said attachment-point in a direction-trans vverse of the longitudinal axis of the dummy flig'htdeckl' J x If sodesired, each of the;first, second and third drive mem-" bets-may be duplicated, bya correspondingly:attached 'sup? port or suspension extensible drive member-respectively some-- to provide :both suspension from above andasupport from--- belowfor the5dummy flight deck. Similarly; the two drive members,.attachedforwarder aft, may eachbetduplieated b i a correspondingly attached extensible drive member whieh is alsoattachedto a point located aft. or forward respectively, of the dummy flight deck. Similarly,-Jthe single=drive member which. is attached also at one sideof the gdummy flightideclt may be duplicated by a correspondingly attached 'extensiblel' drive, memberwhich isalsoattached to a pointlocated ondheopposite side of the dummy flight deck. 70.

Preferably, however, the dummy flight deck is solely suspended from above by three drive members.

Preferably.,the attachment points'of thethree suspension drive; members define an isosceles?triangle,for'example anare attached to the dummy flight deck at opposite sides thereof; are mounted parallel to each other and parallel to the longitudinal axis of'the dummy flight deck, in the rest position thereof. Preferably, the drive member, for providing sway motion', is mounted horizontallyland at right angles to the longitu invention is'capa'ble of providing motion of the dummy flight 749,048. t

deck about six axes, thereby. facilitating simulated motion in all six degrees of freedom of an actual aircraft.

Inorderthattheinventionmay be readily carried into cffect,#one'embodim'entthereof will now be described in detail,

.byjiwayc'of-example, with reference to the accompanying drawings, in which:

FIG: li' is'aperspectiveview, from one side, of a dummy flight-decksuspension arrangement fora ground-based aircraftflight=simulatoraccording to the invention;

FIGQZ is a diagram show'ing the'suspension and movement drive member-arrangement oft'he apparatus of FIG. 1; and

FlG'I S isa schematic circuit diagram of the control arrangementfor'a representative drive member.

ln' the apparatus of FIG. I,'a substantially triangular base 10 for trainee personnel. A

The platform'7 is suspended bythree extensible drive members'4;-=5 and 6; which in this embodiment are hydraulic jacks which ar'e'exten'sible from'about' 12 feet to about 20 feet in .lengtM Thethree' jacks-4, 5 and 6'are' attached by universal joints lkA to' tlie ba's'e-7 near thapices thereof, which apices rounded 'offfor'otherwise cutback asshown in FIG. I. The three-jacks'4f5 and 6 are' dis posed substantially vertically and suspendedfrom' a supporting frame9 by universal joints 1 1B.

Thesupportingfra'me'9, i'sof openwork girder construction and:comprisesessentially an-elevated gantry 9A, of triangular formwith' the'apice's cut backjsupp'orte'd at each cutback apex by -a support name 9B compris'ing two legsand a horizontal base'memb'er.-

Two fore and-aftl'lydraulicjacks l and 2 are attached by universaljoints' '1 1B; one jack to each legof the support frame 9B".-"The' other ends of the jacks] and 2 are attached by universal joints PA to the-ba'se'frame' 7. The two jacks l and'2 are arrangedsubstantially .=horizontally, in the position of inidexte'nsion of the jacks' lf sf'and 6, asshown in FIG. I. The two jac'lt's l and2 are'arranged' parallel to each other and the poin'ts'of attachment ll'Atothe base frame 7 define a line parallel-tothe attachment points of the jacksS and 6 midway .l'aetw"een theattachrr'ient point of jack 4 and the said attachrnent pointsof'jacksS-an'd 6. V

A singletside-jack3 is also arranged substantially horizontally inithe gposition shownin FIG. I, attached to the'base frameT lay a universal joint'lli k and, by a universal joint 1 1B, to'a transverse extension 12 itselfattached to the support 7 fratneQBfiTheaxisof'thejack 3 passes substantially through .the' 'center'of gravity of thebasefra'me7, lies in a lane to which -.the axes'of the jacks l, 5 and 6 are perpendicular and is perpendicular-to the axes of the jacks 1 and 2.

?' Th e centra'l'axis'oftheduimny flight deck 8 passes through thepoint of attachmentofjack' tandintersects the line joining the points of attachmentiofjacks and 6. Jack 4 is therefore the 'frear suspension jaeKandfjacls-S and 6 the front left and front righti'suspension' 'jacks respectively, relatively to the Operation of the strt'icture' may beseenfrom FIG. 1 or the I simplifieddiagramof FIG-f2 and'is as follows: Extension or contraction of all-of jacks 4, sand'fisimultaneously, provides downwards heaveor upwards heave, respectively. Differential a'ction ofjack4 and jacks 5' and" 6 together, provides pitch.

Differential action'of jackss'and'fi, without movement of jack 4,provides'roll; i

Simultaneous extension or contraction of the fore and aft jacks lahdl; provides surge or retardation, respectively. Dlffer'ential operation of jacks I and 2, provides yaw.

Extension or contraction ofjack 3, provides sway to the left or right. respectively.

It may here be noted that a usable system still remains without providing all of the six jacks l to 6, described above. Thus, for simplicity or economy. or in the event of damage or malfunctioning of any jack or its associated control system, some of the jacks and some combinations of the jacks may be replaced by rigid struts.

Thus, if the side jack 3 is replaced by a rigid strut, a five-axis motion system remains, without provision of sway. If the foreand-aft jacks I and 2 are replaced by rigid struts, a four-axis motion system remains, without provision of surge or retardation and yaw. Replacement of both the fore and aft jacksl and 2 and the side jack 3 provides a three-axis motion system providing heave, pitch and roll, only.

The servocontrol system of FIG. 3 functions to actuate a jack 1 having a cylinder 2], attached to a mounting at 22, and a piston 23 connected by rod 24 to a movable load 25.

An input demand signal, designated Wil is applied between input terminals 26 and 27. Terminal 26 is connected to a series resistor 28, for sealing the said input demand signal. The resister 28 forms one of four input resistors 28, 29, 30 and 31, all series connected to one input terminal 33 of a servoamplifier. Input terminal 27 is connected to the input terminal 34 of the servoamplifier 35.

Output displacement of the load 25, by operation of the jack 1, produces corresponding movement of the slider 36 of an answer potentiometer 37, having its outer terminals 38 and 39 connected to a source of positive and negative potential, respectively. The slider 36 is connected by line 40 and by way of series resistor 29 to the input 33 of the servoamplifier 35. Resistor 29 serves to scale the feedback signal from the answer potentiometer 37.

Series resistor 30 serves to damp load resonance and series resistor 31 controls a feedback signal, as is fully described later herein.

The summed signal by way of resistors 28 and 31 is applied to the input of servoamplifier 35. The output of amplifier 35 appears at terminals 41 and 42 and is fed, by way of series resistor 43 to a hydraulic valve control solenoid 44. Resistor 43 provides current feedback to raise the output impedance of servoamplifier 35. The junction of resistor 43 with solenoid 44, is connected by way of series resistor 31, which scales the feedback current signal, to the input of servoamplifier 35.

Output terminal 4] of servoamplifier 35 is connected by way of a resistor 32, which sets the amplifier gain, in a feedback path to the input terminal 33.

Solenoid 44 actuates a hydraulic control valve 45, having an input pressure port 46 and an exhaust port 47. The valve 45 supplies hydraulic fluid, by lines 48 and 49, to the cylinder 2 l portions on the two sides of the piston 23.

Connected into hydraulic lines 48 and 49 are pressure transducers 50 and 51, respectively. The output signals of pressure transducers 50 and 51 are respectively supplied by way of summing resistors 52 and 53 to the input of a summing amplifier 54. The output of amplifier 54 is supplied, by way of a high pass filter 55 and series resistor 30, which as stated serves to damp the effect of load 25 resonance, to the input 33 of servoamplifier 35.

A servocontrol system, similar to that described with reference to FIG. 3, is provided for each one of the jacks I to 6 of the apparatus of FIG. I.

A mathematical analysis of the input signals supplied to the servocontrol systems of jacks I to 6 is unnecessary for a clear understanding of the mechanical operation of the apparatus of FIG. 1. Nevertheless to provide a full understanding of the operation of the system in conjunction with a flight simulator computer, such analysis is given below.

The input signals fed into the servocontrol systems of FIG. 3, associated with the hydraulic jacks l to 6 of FIG. 1, may be defined by the following equations:

The input quantities Wil to Wit) are computed in the flight dynamics computer of an associated flight simulator and are limited to values such that maximum permissible jack displacements are not exceeded.

In the equations for Wil to M6 Kl to K7 are constants related to the geometry of the motion platform and the time constants of the motion platform All the last seven values above are computed variables, including effects of winds and turbulence.

The input quantities Wil to M6 assume a servojack response which is given hy the Laplace transform:

ED z Y W11 1+ S T where y transfer function Wo=servo jack response to input Wi M servo jack input demand S Laplace operator T= time constant. If the transfer function has higher order terms of S in the denominator, then higher derivatives of the computed variables must also be fed into the servoamplifiers. However, the input quantities Wil to M6 are sufficient for most practical purposes.

The effect of the summed inputs on the individual axes are therefore as follows:

Heave-Moves as simulated aircraft minus effect of steady vertical velocity achieved;

Sway-Moves as simulated aircraft minus effect of steady velocity sideways;

Surge-Moves as simulated aircraft minus effect of steady speed forwards;

PitchMoves as simulated aircraft pitch angle;

Roll-Moves as simulated aircraft minus effect of steady roll rate; and

YawMoves as aircraft minus effect of steady yaw rate.

An alternative embodiment of the invention has the dummy flight deck 8 solely suspended from above by the three jacks, but differs from the embodiment described with reference to FIGS. 1 and 2 in that the sway jack 3 is duplicated by a second similar jack on the opposite side of platform 7, both jacks acting through the same point in the body of the platform, but the pair ofjacks l and 2 are replaced by a single jack providing yaw motion.

We claim:

I. A motion simulator for a ground-based flight simulator having a platform for supporting a dummy flight deck, said platform defining longitudinal and transverse axes and having three support'points, first and second of said support points being located on opposite sides of the longitudinal axis from each other and the third support point being located on the opposite side of the transverse axis from said first and second points, a gantry including a support structure located above said platform and having three attachment points defining a triangle, first, second and third controllable extensible and retractable drive members connected respectively between said first, second and third platform support points and said three gantry attachment points, for suspending said platform struction and attached to said support structure at the apex of said frame.

from said gantry, said first, second and third platform supports 9. A ground-based aircraft flight simulator as claimed in being pivotally connected to said gantry and said platform. claim 1, in which the said first, second and third of said drive fourth and fifth controllable extensible and retractable drive members extend downwardly from fixed attachment points on members attached to said platform on opposite sides of said the said gantry to their said attachment points on the dummy longitudinal axis whereby differential operation of said fourth 5 flight deck and support and move the dummy flight deck from and fifth drive members provides skewing of said platform lonabove. gitudinal axis and a sixth controllable extensible and retracti- 10. A ground-based aircraft flight simulator as claimed in ble member attached to said platform for providing lateral disclaim 9, including a support gantry and having first, second pl m n f i platf rm l ngi inal axi and third pairs of said drive members, the drive members of A motion simulator as claimed in F in which said 10 each pair extending upwardly from fixed points to their atfourth and fifth drive members are attached to said platform at tachment oints on the dummy flight deck and extending points between the Said lhil'd drive member and i first and downwardly from fixed attachments on the said gantry to their second drive members. said attachment points on the dummy flight deck, respective- 3. A motion simulator as claimed in claim 2, in which said l foui'ih and fifth drive mcmbci's are g axefi'piiiaiiei II. A ground-based aircraft flight simulator as claimed in under conditions of equal extension and both extend from the l i 9, h i a i of said drive members including said said platform attachment points in the same direction relativcfif h one f id drive members, the other drive member of y l h Platform longitudinal i I i said pair being similarly attached to the dummy flight deck A motion Simulator as claimed in claim in which the and operable for lateral movement of its attachment point in platform part between the said platform attachment points of h Same id t r e dire tion. the fourth and fifth drive members and the third drive member ]2 A db d air aft flight simulator as claimed in is iapei'edih the direction ofsaid third drive memberclaim 9, having a pair of said drive members including said A motion Simulator as Claimed in Claim i, in which Said fourth one of said drive members, the other drive member of sixth drive member is attached to the said platform at a point id i b i tt h d go the dummy flight deck at a point I between Said third drive member and one of Said iii-5i and laterally spaced from the longitudinal axis thereof and on the Second drive membeis- I opposite side thereof from that of said fourth one of said drive A motion simulator as claimed in claim 5, which member whereby differential operation of said pair of drive Said Piaifomi is of subsmmiaiiy equiiaiei'ai vtiiaiigiiiai' form members provides skewing of said longitudinal axis of the between the said support points, and the said gantry support dummy fli ht d k structure is of substantially equilateral triangular form, 13 A d.b d i f fli ht simulator as claimed in between said attachment P claim 12, in which both drive members of said pair, which in- A motion Simulator as claimed in Ciaim in which eludes said fourth one of said drive members, themselves form 'y is ofti'ipod construction I one drive member of a pair, both drive members of each said a A motion simiiiaior as Ciaimed in ciaim in w h pair having the same point of attachment as each other to the tripod feet of said gantry are each of iriangiiiai' frame dummy flight deck, the two drive members of each said pair extending in opposite fore-and-aft directions therefrom. 

1. A motion simulator for a ground-based flight simulator having a platform for supporting a dummy flight deck, said platform defining longitudinal and transverse axes and having three support points, first and second of said support points being located on opposite sides of the longitudinal axis from each other and the third support point being located on the opposite side of the transverse axis from said first and second points, a gantry including a support structure located above said platform and having three attachment points defining a triangle, first, second and third controllable extensible and retractable drive members connected respectively between said first, second and third platform support points and said three gantry attachment points, for suspending said platform from said gantry, said first, second and third platform supports being pivotally connected to said gantry and said platform, fourth and fifth controllable extensible and retractable drive members attached to said platform on opposite sides of said longitudinal axis whereby differential operation of said fourth and fifth drive members provides skewing of said platform longitudinal axis and a sixth controllable extensible and retractible member attached to said platform for providing lateral displacement of said platform longitudinal axis.
 2. A motion simulator as claimed in claim 1, in which said fourth and fifth drive members are attached to said platform at points between the said third drive member and said first and second drive members.
 3. A motion simulator as claimed in claim 2, in which said fourth and fifth drive members are arranged with axes parallel under conditions of equal extension and both extend from the said platform attachment points in the same direction relatively to the platform longitudinal axis.
 4. A motion simulator as claimed in claim 3, in which the platform part between the said platform attachment points of the fourth and fifth drive members and the third drive member is tapered in the direction of said third drive member.
 5. A motion simulator as claimed in claim 1, in which said sixth drive member is attached to the said platform at a point between said third drive member and one of said first and second drive members.
 6. A motion simulator as claimed in claim 5, in which the said platform is of substantially equilateral triangular form, between the said support points, and the said gantry support structure is of substantially equilateral triangular form, between the said attachment points.
 7. A motion simulator as claimed in claim 1, in which the gantry is of tripod construction.
 8. A motion simulator as claimed in claim 7, in which the tripod feet of said gantry are each of triangular frame construction and attached to said support structure at the apex of said frame.
 9. A ground-based aircraft flight simulator as claimed in claim 1, in which the said first, second and third of said drive members extend downwardly from fixed attachment points on the said gantry to their said attachment points on the dummy flight deck and support and move the dummy flight deck from above.
 10. A ground-based aircraft flight simulator as claimed in claim 9, including a support gantry and having first, second and third pairs of said drive members, the drive members of each pair extending upwardly from fixed points to their attachment points on the dummy flight deck and extending downwardly from fixed attachments on the said gantry to their said attachment points on the dummy flight deck, respectively.
 11. A ground-based aircrafT flight simulator as claimed in claim 9, having a pair of said drive members including said fifth one of said drive members, the other drive member of said pair being similarly attached to the dummy flight deck and operable for lateral movement of its attachment point in the same said transverse direction.
 12. A ground-based aircraft flight simulator as claimed in claim 9, having a pair of said drive members including said fourth one of said drive members, the other drive member of said pair being attached to the dummy flight deck at a point laterally spaced from the longitudinal axis thereof and on the opposite side thereof from that of said fourth one of said drive members, whereby differential operation of said pair of drive members provides skewing of said longitudinal axis of the dummy flight deck.
 13. A ground-based aircraft flight simulator as claimed in claim 12, in which both drive members of said pair, which includes said fourth one of said drive members, themselves form one drive member of a pair, both drive members of each said pair having the same point of attachment as each other to the dummy flight deck, the two drive members of each said pair extending in opposite fore-and-aft directions therefrom. 